Pre-press leak indicator sealing rings for press fitting arrangements are largely known in the prior art. One example of such a known sealing ring is shown in FIGS. 9a and 9b. As illustrated, a press fitting arrangement 100 comprises a press fitting 110, a sealing ring 120 and a tube 130 with a gap 140 being provided between the press fitting 110 together with the sealing ring 120 and the tube 130 to allow a fluid flow 150 from the inside of the tube 130 to the outside of the press fitting arrangement 100. The press fitting 110 is provided with two cylindrical portions 111, 112 between which a bead 113 is arranged in order to house the sealing ring 120, with the bead 113 being provided with a flank 114 facing the free end of the press fitting 110.
The gap 140 is provided between the sealing ring 120 and the tube 130 in the region of the bead 113 due to choosing the cross-section of the sealing ring 120, that is the cross-section perpendicular to the direction of the fluid flow 150, to be substantially circular with a sealing ring diameter D1 being smaller than the difference between the inside bead diameter and the outside tube diameter. In usage, prior to applying a pressing action in order to obtain a fluid tight connection between the press fitting 110 and the tube 130, a fluid flow force F1 acting on the sealing ring 120 can exceed the force F2 of the fluid flow 150 within the gap 140, see FIG. 9a, such that the sealing ring 120 will move towards the flank 114 of the bead 113 which will result in a downward movement of the sealing ring 120 reducing the gap height G1 until the gap 140 and, thus, the leak path of the press fitting arrangement 100 is closed as shown in FIG. 9b. 
A structure as discussed with respect to FIGS. 9a and 9b is in particular known from DE 101 18 955 C2.
It is also known to increase the gap height G1 in an arrangement discussed with respect to FIGS. 9a and 9b in order to avoid a pre-press closure of the leakage path by, e.g., modulating the sealing ring contour as, for example, disclosed in WO 2004/068018 A1, DE 298 13 935 U1, EP 0 985 113 B1 or JP 08226582 A. The sealing ring known from JP 08226582 A has an outer diameter made substantially equal to an inside diameter of the bottom of a bead of a press fitting within which the sealing ring is housed and an inside diameter made substantially equal to an outside diameter of a tube inserted within the press fitting. In addition, the known sealing ring is provided with a recess defining a fluid flow passage between the sealing ring and the bottom of the bead on the one hand and between the sealing ring and the outer surface of the tube on the other hand, and two projections bordering said recess, each with two substantially triangular extended portions engaging in both side edges of the bead in order to inhibit the displacement of the sealing ring and, thus, the flow passages prior to applying a pressing action.
Further developments of known press fitting arrangements, and in particular sealing rings therefor, are desired in order to ensure the pre-press leak indicator function.